Our guide explained that the piranhas in the Ecuadorian tributaries of the Amazon were far better fed than their Brazilian counterparts and were therefore of "no particular danger" to humans.
In a place as alien and forbidding as the Amazon it seemed pointless to place anything less than complete faith in our local guide. But after four days of wading through rivers on the assumption that piranhas were only a Brazilian menace, it was unnerving to realise we had unwittingly staked so much on his faith in the fickle culinary habits of the local carnivore.
However after four days in the jungle with this man, it had become obvious that he thrived on delivering such casual one-liners and watching the reaction of unsuspecting travellers like ourselves.
Our guide, a man with the unlikely but entirely apt name of Adonis, was known in his village as a notorious practical joker. One of his favourite tricks was to take travellers downriver in a dug-out canoe, persuade them to take a swim and then calmly throw a fishing line over the side, reel in a piranha and watch their reaction.
We first met Adonis in his small Amazon village in Eastern Ecuador, near where the Spanish conquistador, Francisco Orellana began his epic trans-Amazon journey in search of El Dorado in 1539. Towering over us with a machete hanging from one side of his belt, a huge carving knife strapped to the other side and a lollypop in his mouth, we knew immediately that this was the perfect man to show us the jungle.
Standing astride the bow of our dug-out canoe like a Nelson of the Amazon, he guided our group deep down the brown waters of the Rio Napo - a major tributary of the Amazon River.
Some hours later we disembarked at a point on the river distinguishable only to Adonis. Undeterred by our blank stares at the seemingly impenetrable wall of creepers and vines which stood between us and our distant lunchtime spot, Adonis wielded his machete as we might wield a toothpick and proceeded to carve a path for us.
Entering the Amazon rainforest for the first time is like walking into the plot of a 1950s science fiction film where some mysterious power has transformed everything into twice its normal size. Butterflies are the size of small birds, the "small" birds are big birds and the spiders are so big that they actually catch and eat the birds.
The bird-eating spider found in these parts is the largest in the world and not a sight for the faint hearted.
Oversized vines do their best to overrun and strangle massive trees and the air is thick with huge insects which look more like clumsy exotic mutations than natural creations.
More than half of the insect species in the world come from the Amazon and Adonis would frequently pause from his path-carving to describe the different varieties and occasionally even taste them.
At one point he persuaded us to taste some termites, which were a local delicacy.
When we complained that they tasted slightly wooden he laughed loudly, strode over to a nearby plant, hacked it open and produced some delicious lemon-flavoured ants to help take the termite taste away.
We slept at a peaceful jungle camp flanked on one side by a small river and on the other side by dense jungle. That night Adonis brewed some of the local firewater for us and entranced us with fascinating tales of the jungle.
Over the next three days Adonis did his best to turn our whole group into trainee tarzans. When we weren't taking long treks or canoe trips through the jungle, we were learning the finer points of blow-dart hunting and vine swinging.
He even gave us a step by step description of how shrunken heads are shrunk, describing the process as "very simple and straightforward."
After once last memorable candlelit dinner and further tales of the Amazon, Adonis finally guided our group back upriver to ‘civilisation’. I am honestly not sure which was more memorable - the incredible and endlessly fascinating Amazon rainforest or this utterly enigmatic and charismatic guide.